All the currently known transiting exoplanets with a measured mass (with precision better than 20 %) are displayed in Fig. REF .
TOI-1201 b falls in the realm of Neptune-sized planets above the M-dwarf radius valley [1]}.
In this regard, the density of \(\rho _b = 2.45^{+0.48}_{-0.42}\)  g cm\(^{-3}\)  suggests that its composition is in line with an Earth-like rocky core with an H-He envelope of 0.3 % by mass, following the theoretical composition models from [2]}https://lweb.cfa.harvard.edu/~lzeng/planetmodels.html. Likewise, it is consistent with being a water world, signifying that its internal composition is rather dominated with H\(_2\) O in the form of ices and fluids, which is also a very plausible scenario in the realm of planet formation [3]}, [4]}.
Atmosphere characterization via transmission spectroscopy paired with precise mass and radius determinations and a good set of interior models could aid in breaking this ambiguity of its interior architecture.
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